Proton Recoils in GaN & Upcoming RF GaN Work
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Proton Recoils in GaN & Upcoming RF GaN Work
1To be presented by Jason Osheroff at the 2021 NEPP Electronics Technology Workshop (ETW), NASA GSFC, Greenbelt, MD, June 14-17, 2021.
Jason Osheroff
jason.m.osheroff@nasa.govNASA Goddard Space Flight Center
Acronyms/Abbreviations• AMP: Amplifier• CIF: Center Innovation Fund• COTS: Commercial Off The Shelf• DC: Direct Current• DDD: Displacement damage dose• DUT: Device Under Test• EMPC: Experimental and Mathematical Physics Consultants• GSFC: Goddard Space Flight Center• HEMT: High Electron Mobility Transistor• LBNL: Lawrence Berkeley National Lab• LLRF: Low Level Radio Frequency • LET: Linear Energy Transfer• MCNP: Monte Carlo N Particle• NEPP: NASA Electronics and Packaging Program• REAG: Radiation Effects and Analysis Group• RF: Radio Frequency• SEE: Single Event Effects• SRIM: Stopping Ranges of Ions in Matter• TID: Total Ionizing Dose
2To be presented by Jason Osheroff at the 2021 NEPP Electronics Technology Workshop (ETW), NASA GSFC, Greenbelt, MD, June 14-17, 2021.
Outline
• Proton Recoils in GaN*– SRIM– MCNP– Results– Conclusion– Future work and
implications
3To be presented by Jason Osheroff at the 2021 NEPP Electronics Technology Workshop (ETW), NASA GSFC, Greenbelt, MD, June 14-17, 2021.
• RF GaN HEMTs– Motivation– DUT selection– Test bench– Challenges & Next steps
*All figures from J. Osheroff et al., “LET and Range Characteristics of Proton Recoil Ions in Gallium Nitride (GaN),” doi:10.1109/TNS.2021.3050980
Proton Recoils in GaN - SRIM
4To be presented by Jason Osheroff at the 2021 NEPP Electronics Technology Workshop (ETW), NASA GSFC, Greenbelt, MD, June 14-17, 2021.
• Stopping Ranges of Ions in Matter (SRIM) calculates the LET and range as a function of energy for a given ion species in a given material
• Hydrogen through Germanium* are all possible recoils
LET as a function of ion energy in GaN Range as a function of ion LET in GaN
Proton Recoils in GaN - MCNP
5To be presented by Jason Osheroff at the 2021 NEPP Electronics Technology Workshop (ETW), NASA GSFC, Greenbelt, MD, June 14-17, 2021.
Source Gate Drain
2DEG
GaN
Substrate
25 nm AlGaN
2 µm GaN
1x109 Protons 100 µm beam radius
1x1 cm target AlGaN
• MCNP simulations • 1x109 incident protons at multiple energies 50-1000 MeV• Both GaN (see Fig. 3 below) and Si targets for comparison• Determine the actual populations of secondary recoil ions
in GaN from proton irradiation • Determine the species and energy of each recoil
(left) Scenario for MCNPX simulations, including proton source and AlGaN/GaN target. (right) simple cross section of a typical GaN HEMT.
Proton Recoils in GaN - Results
6To be presented by Jason Osheroff at the 2021 NEPP Electronics Technology Workshop (ETW), NASA GSFC, Greenbelt, MD, June 14-17, 2021.
• Higher Z ions present in GaN• Notable peaks around Si (N=14) for Si target • Notable peaks around N (N=7) and Ga (N=31) for GaN target
Recoil Ion population in Si for 50, 200, and 1000 MeV proton beams
Recoil Ion population in GaN for 50, 200, and 1000 MeV proton beams
Proton Recoils in GaN - Results
7To be presented by Jason Osheroff at the 2021 NEPP Electronics Technology Workshop (ETW), NASA GSFC, Greenbelt, MD, June 14-17, 2021.
LET of recoil ions in Si for various incident proton energies
LET of recoil ions in Si for various incident proton energies
• Recoil LET in Si is largely unaffected by incident proton energy between 50-1000 MeV
• In GaN, upper-end recoil LET increases with proton energy and exceeds that seen in Si, reaching up to ~27 MeV-cm2/mg
Proton Recoils in GaN - Conclusions
8To be presented by Jason Osheroff at the 2021 NEPP Electronics Technology Workshop (ETW), NASA GSFC, Greenbelt, MD, June 14-17, 2021.
• Looking at individual recoil ions from the MCNP output we find that high LET recoils are dominated by elastic recoils
• Similar approximations can be made for GaAs, SiGe, diamond etc. based on target mass
Theoretical upper limit for Ga in GaN and Si in Si elastic “head-on” recoils
Proton Recoils in GaN – Future Work and Implications
9To be presented by Jason Osheroff at the 2021 NEPP Electronics Technology Workshop (ETW), NASA GSFC, Greenbelt, MD, June 14-17, 2021.
• Similar approximations can be made for GaAs, SiGe, diamond etc.
• High energy, high flux proton environments may pose an increased risk of SEE in GaN as opposed to Si
• In materials such as GaN that have high TID and DDD tolerance it may be possible to do proton SEE irradiations with a high enough fluence to achieve recoils with an LET of ~27 MeV-cm2/mg
• Future work would include proton testing of known GaN devices with accompanying simulation (LETTH = 15-20 MeV-cm2/mg with >500 MeV protons)
RF GaN
10To be presented by Jason Osheroff at the 2021 NEPP Electronics Technology Workshop (ETW), NASA GSFC, Greenbelt, MD, June 14-17, 2021.
11To be presented by Jason Osheroff at the 2021 NEPP Electronics Technology Workshop (ETW), NASA GSFC, Greenbelt, MD, June 14-17, 2021.
RF GaN HEMT SEE testing – Motivation
• Worst-case radiation test conditions– RF mode vs. DC only
• Laser vs. heavy ion testing
• Device factors resulting in SEB susceptibility– Output power– Frequency range– Drain voltage
RF GaN HEMT SEE testing – DUT Selection
12To be presented by Jason Osheroff at the 2021 NEPP Electronics Technology Workshop (ETW), NASA GSFC, Greenbelt, MD, June 14-17, 2021.
Table of Proposed Test DevicesManufacturer Part # Frequency Range (GHz) VDS (Volts) Power (Watts)CREE/Wolfspeed CGHV59350F 5.2-5.9 50 450
CREE/Wolfspeed CGHV59070F 4.4-5.9 50 76
CREE/Wolfspeed CGH31240F* 2.7-3.1 28 240
CREE/Wolfspeed CGHV40200PP 1.7-1.9 (up to 3) 50 218
Qorvo QPA2237* 0.3-2.5 32 10
DUTs selected to form matrix of voltage, frequency, and power properties
Table of proposed GaN HEMTs for SEE testing
RF GaN HEMT SEE testing – Test Bench
13To be presented by Jason Osheroff at the 2021 NEPP Electronics Technology Workshop (ETW), NASA GSFC, Greenbelt, MD, June 14-17, 2021.
• 2Gs/s Oscilloscope• Network Analyzer• Spectrum Analyzer• LLRF Generator• 2x Keithley 2400 series
• DUT Gate• PRE-AMP control
• 2x BK Precision • High I for PRE-AMP Drain• High V for DUT Drain
• PRE-AMP• RF GaN HEMT technology!
• Various RF circuitry to deliver and dissipate power safely
• Data Acquisition system
RF test equipment at GSFC REAG Lab
RF GaN HEMT SEE testing – Challenges and Next Steps
14To be presented by Jason Osheroff at the 2021 NEPP Electronics Technology Workshop (ETW), NASA GSFC, Greenbelt, MD, June 14-17, 2021.
• Cooling– Vibrational considerations for laser testing
• Decoupled fan– Vacuum compatible cooling at LBNL
• Liquid cooling• Power compatibility
• DUT acquisition for round 2 laser and heavy ion testing
Acknowledgments
• NASA Electronics Parts and Packaging Program• Recoils in GaN
– Thomas M. Jordan of Experimental and Mathematical Physics Consultants (EMPC) for modifying the MCNP code.
• RF GaN HEMT– GSFC Code 561 and CIF for support of RF equipment– John Scarpulla from The Aerospace Corporation
15To be presented by Jason Osheroff at the 2021 NEPP Electronics Technology Workshop (ETW), NASA GSFC, Greenbelt, MD, June 14-17, 2021.
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